Chapter 18 - Solid State Fermentation and Its Applications

Abstract

This chapter reviews the recent advances in solid state fermentation (SSF) system research and development. SSF can be directly carried out with abundant low-cost biomaterials (starch, cellulose, lignin, hemicellulose, and chitin etc.) with minimal or no pretreatment, and thus is relatively simple, uses less energy than submerged fermentation (SmF), and can provide unique microenvironments conducive to microbial growth and metabolic activities. Organic acids and industrial enzymes are the two most common categories of products from SSF. With little or no free water in the fermentation bed, SSF generates higher volumetric productivity and less waste water. The extraction of products from the fermentation bed provides more concentrated solutions than submerged fermentation for the downstream processes. All the advantages of SSF suggest that SSF has a high potential as a much more economical industrial process. However, its industrial applications are very limited, especially in western countries. The main problem is that the development of a simple and practical automated fermenter for SSF processes has not yet been achieved. Traditionally, SSF is carried out in trays or packed-bed bioreactors. These conventional reactors are simple to construct and widely used, but cannot provide enough mass and heat transfer, which are very important for fermentation processes.